Current estimates place the number of envelopes used annually in the United States at over 100 billion. A significant percentage of these envelopes are used in connection with bulk mailings, and are accordingly filled, addressed and processed by a variety of automated devices. A lynchpin of all automated processes is the automatic envelope inserter. Automatic inserters are large, complex devices that are loaded with contents to be inserted (e.g., individual letter sheets and/or fillers) and envelopes in which these contents are to be inserted. Other devices such as binders, that bind inserts together (into a books, catalogs, newspapers or magazines), presses that apply logos and decoration, addressing devices, collating and a variety of other devices are also used selectively to process individual sheet-like materials in bulk mailing and other processes. These various devices can be termed generally “utilization devices” as they utilize sheet-like materials that are typically dispensed in stacks.
Reference is made generally to U.S. Pat. No. 6,698,748, entitled SYSTEM AND METHOD FOR SINGULATING A STACK OF SHEET-LIKE MATERIALS, by H. W. Crowley, the teachings of which are expressly incorporated herein by reference. FIG. 1 of the incorporated patent shows, by way of background, a high-volume envelope inserter in current use by industry and representing generally the state of the prior art. The depicted exemplary inserter (100—in which the following numbers in parenthesis represent reference numbers in the incorporated patent) is a large, modular unit that combines various contents stored in hoppers (not shown) in the rear (102) of the device and that directs (arrows 104 and 106) contents (105) onto a raceway (108) downstream (arrow 110) toward a stack of envelopes (112). At each point along the raceway, additional insert sheets are added to the contents. These contents may be folded, or otherwise compacted, to fit within the selected envelope by mechanism within the inserter. Envelopes are drawn from the stack (112), and directed downstream (arrow 114) to an inserting station (116) at which the closed-but-unsealed envelope flaps (118) are opened so that the final contents (120) can be inserted thereinto. The filled envelopes (122) are then transferred further downstream (arrow 124) to a stacking position or further-processing module (not shown).
Industrial inserters, referred to generically as swing-arm inserters, are available from a variety of well-known companies including Bell & Howell (Phillipsburg), as well as by Mailcrafter (Inserco model), Pitney Bowes (AMOS model), EMC Document Systems (Conquest Lsi model) and HM Surchin (Cornish model). A rotary variation is made by Buhrs (BB300 and BB 500) series. One more-specific example is the Bell & Howell Imperial™.
Most inserters cycle at least 10,000 per hour without any material. However, once the various hopper materials are inserted into the envelopes, the net production is significantly slower. Due to paper handling problems, swing-arm inserters often net less than one third of their capabilities. A typical swing-arm device in production may net less than 3000 completed envelopes per hour. After careful study, it is now recognized that there are several issues of unreliability in the feeding of materials in conventional inserter devices. Many device areas are subject to jams. In fact, the design of these inserters has not changed significantly in 30 years. And for that matter, they have changed little since their invention 70 years ago, as exemplified by U.S. Pat. No. 2,325,455.
A number of inefficiencies and disadvantages have been noted in prior art swing arm inserters, for example, the overlying swing-arm structure of the inserter is complicated and difficult to access owing to a large number of interconnecting shafts that drive the various arm and gripper components. These shafts require a complicated series of adjustments and tuning to insure proper function. They also obscure access to, and view of, the contents feed hoppers, and more generally interfere with the operator's loading, unloading and operation of the device. In addition, the operative mechanism of the prior art inserter resides beneath a heavy feed table, which is only accessible from beneath. Repair and service of the mechanism is therefore inconvenient and requires the service person to stoop and crawl beneath the device for even the most basic tasks. Other aspects of prior art inserters are similarly deficient. For example, adjusting the size of an envelope in the envelope feed hopper requires adjustments to several elements on the downstream feed table. This is because the upstream end of the envelope hopper is fixed, while the downstream end must be moved, and this causes the synchronization of contents feed components with the envelope leading edge to change whenever the size is readjusted. Likewise, the inserter is constructed with a housing and table that are placed at an average height for an average worker with no easy way to change that height to accommodate shorter or taller operators. Also, while prior art inserters may contain a facility for dealing with the exhaustion or jamming of a “primary” contents hopper by providing a backup, or secondary contents hopper, such backup implementations are non-intuitive and difficult for an operator to implement.
Moreover, prior art inserters generally lack straightforward design in their individual components and power-transmission, making them more expensive to manufacture, more difficult to repair, and more prone to misfeed, due to bad tuning (given the many interconnected parts, which must interact perfectly).
Accordingly, it is highly desirable to provide an inventive high-speed envelope inserter, which intelligently addresses a variety of the foregoing concerns and thereby provides a more-serviceable, faster-running and generally more-reliable device.